Centrifuge apparatus



March 2, 1954 E' c s 2,670,898

CENTRIFUGE APPARATUS Filed May 22, 1950 2 Sheets-Sheet l INVENTOR. 42 fowa/a Ci p/d e/s Y ATTORNEYf March 2, 1954 5 (5f c s 2,670,898

CENTRIFUGE' APPARATUS Filed May 22, 1950 2 Sheets-Sheet 2 IN VEAC TOR. 56 fowa/o 6*. Make/5 QZQML 'Ihave found it desirable: in such Patented Mar. 2, 1954 2,670,898 CENTRIFUGE APPARATUS Edward G. Pickels, Pa

Alto, cans, assignor a Specialized Instruments Corporation, Belmont, Cali'fl, a corporation of California Application May 22, 1950;"Serlal No. 163,392 13 Claims. (01. 233-1) -This invention relates generally to centrifuge apparatus; for laboratory separating operations, andtparticularly to apparatus of theultra centrifugetype,, wherein the rotor may be driven at speeds ranging up to 40,000 R. P. M. or more.

Ultraycentrifuges generally employ a vacuum chamber in which the rotor is disposed, and

which can besevacuated for the higher rotative speeds employed. The rotor is'coupled to a driving spindle, which inturn connects with speed multiplyinggearing and. a driving motor, both located exterior of the vacuum chamber. Considerable care must be taken with such a machine in order to: avoid operating hazards. For example it is'inadvisable to operate the machine at rotative speeds ranging above about 5,000 R. P. M. without first taking the precaution to close and evacuate the vacuum chamber; Also one must take care to vent the vacuum at the end of a run,

before attempting to open the vacuum chamber.

machines to provideaa special type of seal about the driving spindle, and which seal is continuously supplied with 'oil. The operator must take care to maintain an: adequate supplylof oil. for this seal in order that it may function properly during normal operation under vacuum.

Ingeneral it is an object of the-present invention to provide centrifuge apparatus of the above type having safety features which: obviate the principal operating hazards involved.

' Y 'Itisa further object of the invention to provide improved centrifuge apparatus having automatic provision for preventing operation atthe higher 'rotative speeds when the. vacuum chamber is open, or-when the chamber is notlocked in: closed position, or when the vacuum pump is not operating.

-It-is another object of the'invention to provide a machine of the above character with a manually operatedstarting member which makes certain that the venting valve for the vacuum chamber is closed before the-vacuum pump is started.

Another objectof the invention is to provide a centrifuge. machine of the above character in which means is employed to prevent the: start of a: run if the amount of. oil for supplying the: vacuumseal is less than a predetermined amount.

*Another object of the: invention. isto providesa simplified type of control for an ultra centrifuge, and which is characterized by a singlemanual operatingmem-ber which when operated will: serve toifoperate'. the locking means for the" vacuum chamber cover, the 1 vent; valve for: the. vacuum chamber; and switching. means for-controlling operation of the vacuum pump. In conjunction with. the-object just stated, itis a further object of the invention to provide anovel interlock in conjunction with such manual control member, whereby it is impossible to unlockthe cover during a normal high speed operation, and impossible to initiate a complete operating cycle without providing a proper quantity of oil for the vacuum seal.

Further objects and features of the invention will appear from the following description in which the preferred embodiments are set forth in detail in conjunction with the accompanying drawing. 1

Referring tothe drawing:

Figure l is a schematic view partly-in section illustrating centrifuge apparatus incorporating the present invention.

Figure 2 is an enlarged schematic-view taken along the section line -22 of Figure 1.

Figure 3 is .anenlarged cross-sectional detail taken along the line 3'3- of Figure 1.

Figure 4 is across-sectional detail illustrating an oil lubricated vacuum seal for'the'drive spin- ,dle of therotor.

Figure l of the drawing schematicallyillustrates-acentrifugecomprising a rotor I 0 disposed within the vacuum chamber H. The vacuum chamber is provided with a cover I2 adapted to slide horizontally between open and-closed positions. and adapted in closed condition tobe sealed whereby the interior of the chamber can be evacuated. Suitable means can be used for moving the cover between open and closed positions, such as a cable operator, actuated by the rotatable knob 13.

Exterior of the vacuum chamber there is an electric drivingmotor I4, which serves to drive the spindle to which'the rotor is coupled, through the speed multiplying gearing [6. This gearing, and the manner in which itis coupled to the rotor Ill, can beconstructed as disclosed and claimed in my copending application Serial No. 163,393, filed May 22', 1959, and entitled Centrifuge Appara- As disclosed in said copending application a rategenerator i1 is incorporated in connection with the drive, and connects with a speed controller as will be presently explained. Interposed l6 and the bottom wall of the vacuum; chambenthere is a vacuum seal 1-9 as will be presently described.

Located; at somev convenient position there-is a manually operated member 2| which may be; in the formofaknob mounted'upon the rotatable shaft' ZZ'. This shaft is rotatably supported by suitable means 29 and may be provided with suitable stops whereby the angular movement is limited.

An air valve 23 is connected by pipe 24 to the interior of the vacuum chamber, and when this valve is open the interior of the chamber is vented to the atmosphere. The operating member 25 of the valve 23 is directly mechanically connected to the shaft 22. For the one operating position of member 2!, the valve 23 is open, and for the other operating position it is closed. It is convenient to employ a valve of the globe type with a soft rubber seat and a threaded operating stem.

Locking means is provided for positively looking the cover l2 in closed position. Thus a rod 25 is slidably mounted alongside the vacuum chamber, and has its upper end (Figure 3) extending through the guide opening 21. The rear edge 28 of the cover clears the rod 25 when the cover is'fully closed. Rod 22 carries a radially extending finger or arm 29, which when rotated in a counterclockwise direction as viewed in Figure 3, is adapted to engage between the two collars 3| and 32, which are mounted upon rod 26. Thus counterclockwise rotation of the rod 22 serves to lift the rod 22 into locking position, 'as illustrated in dotted lines in Figure 3.

With the arrangement described above it will be evident that manual operation of the knob 2i serves to simultaneously operate both the cover locking means and the vent valve for venting the vacuum chamber to the atmosphere.

During a normal run the interior of the vacuum chamber is evacuated by the pump 33, which is shown being operated by the electric motor 34.

w The suction side of the pump is connected to the vacuum chamber by a hose or pipe 35.

In order to provide lubricant for the seal I9 and for the vacuum pump during a normal run,

an oil receptacle 31 is provided, which has a flexible fluid connection 38 to the seal 19. Another fluid connection 39 serves to connect the vacuum side of the seal 19 with the pipe 36 or directly to the suction side of the pump 33 as indicated. Oil overflowing from the vacuum pump is shown being discharged by line 41 to the catch pan 42.

The receptacle 31 is preferably associated with means whereby when this receptacle does not have an adequate amount of oil the knob 2| cannot be rotated to close the valve 23 and to close certain switches to be presently described. Thus the receptacle is supported by the mounting 43, which in turn is carried by the tongue or fulcrum 44. A counterweight 46 insures movements of the receptacle 31 to the left or to the right, depending upon the amount of oil present. A finger 41 extends upwardly from the mounting and in juxtaposition to one face of a disc 48 which is secured to or forms a part of the knob 2|. The disc carries a lug or pin 49 which is adapted to engage the finger 41 for that position of the latter corresponding to the position which it assumes when there is an insufficient amount of oil in the receptacle 31 for a normal run. When an adequate amount of lubricating oil is in the receptacle 31, mounting 43 tips to the right to bring the finger 41 to an out-of-the-way position with respect to pin 49, thus permitting the knob 2i to be turned in a direction to close the valve 23, lock the cover, and operate the above mentioned switches.

As previously stated the vacuum seal Hi can be made as disclosed in my copend g app i ation Serial Number 163,393. Such a seal is illustrated in Figure 4. The rotor l9 in this instance has its lower side provided with the opening or socket 5|, which is adapted to receive the thimble-like driving member 52. Driving member 52 is attached to the upper end of the spindle 53. The spindle extends downwardly through the spud 54, and through the rigid hollow drive shaft 56. As described in the aforesaid application, the lower end of the drive shaft 56 has a driving connection with the lower end of the spindle.

The spud 54 is provided with a bore 51 through which the spindle 53 extends, and which accommodates the annular members 58 and 59. These members are bored to snugly fit the spindle 53, and are machined externally to loosely fit the bore 51. They are provided with peripheral grooves to receive the resilient 0 ring seals GI, 62, which serve to frictionally retain the memhere 58 and 59 against rotation, and to form seals between members 58 and 59 and the side surfaces of the bore 51. The adjacent end faces of members 58 and 59 are provided with radially extending grooves 63, 54, which serve to convey oil from the inlet duct 66, to the running clearance between member 58 and the spindle 53. Both the members 58 and 59 are held down in their operating positions'by the sleeve 61. Above the member 58 the sleeve 61 is provided with a port 58, whereby oil collecting above member 58 may flow through this port, and then through duct 59 into the adjacent space 11 which is formed within the resilient seal sleeve 12. This seal can be formed of suitable material such as resilient rubber, and extends between the spud '54 and the chamber wall It. Oil is drained from ance between member 58 and the spindle, to accumulate above member 58. From the space above member 58 such oil flows through port 68, duct 69, space 1!, and from thence through duct 13 and line 38 to the lubricating system of the vacuum pump 33.

In conjunction with my machine it is desirable to employ a suitable speed controller 16 and preferably one of the electronic type. A suitable elec tronic speed controller for this purpose has been disclosed in an article entitled Electronic speed control by applicant and P. F. Scofield, published in Electrical Manufacturing, January 1950 edition, page 66. The controller in that instance is of the saturable reactance type, and may be employed to control acceleration, speed of operation, and deceleration. Line 11 (representing a multiconductor cable) represents circuit connections from the speed controller to the electric motor 14. Line 18 similarly represents circuit connections to the rate generator l1. Device 19 represents a speed control adjustment under the control of the operator, and which is associated with the circuits of the speed controller. Device 8| represents a timer which is likewise associated with the circuits of the speed controller, and serves to control the time period that the rotor is driven at a prescribed .speed. Line 82 represents circuit connections to acontrolling switch 33. As disclosed in the aforementioned publioperation of said air valve simultaneously with operation of said locking rod. j

4. In centrifuge apparatus of the type including a centrifuge rotor disposed in a chamber which is adapted to be evacuated by a vacuum pump, the chamber having a cover movable between open and closed positions, mechanical means for locking the cover in closed position, a manually operated member movable between limiting positions for releasing said locking means to permit opening of the cover or for causing said locking means to lock the cover in closed position, circuit means including a switch to control operation of the vacuum pump, and means for effecting operation of said controlling switch responsive to operation of said locking means.

5. In centrifuge apparatus of the type including a centrifuge rotor disposed in a chamber which is adapted to be evacuated by a vacuum the chamber having a cover movable between open and closed positions, mechanical means for locking the cover in closed position, valve means for venting the chamber to the atmosphere, circuit means including a control switch for controlling operation of said vacuum pump, and common manually operated means for releasing said locking means and for operating the valve means to vent the chamber and for operating said control switch, whereby said vent valve is operated to vent the vacuum chamber when said manually operated means is operated to unlock the cover, and whereby said controlling switch is operated to effect operation of the vacuum pump only when said manually operated means is operated to lock the cover in closed position.

6. In centrifuge apparatus of the type including a centrifuge rotor disposed in a chamber which is adapted to be evacuated and which has a cover movable between open and closed positions, together with a drive spindle to which the rotor is coupled and drive means exterior of the chamber for turning the spindle; vacuum sealing means surrounding the spindle, said sealing means having provision for introducing and re moving oil from the same, an oil supply reservoir having a fluid flow connection to said sealing means, balanced means for mounting said reservoir and including a member assuming limiting positions responsive to the amount of .oil in the reservoir, a manually operated member adapted to be moved to initiate an operation of the rotor, and means serving to cause said first member when in one position of the same to lock said last named member against movement to start a run.

'7. In centrifuge apparatus of the type including a centrifuge rotor disposed in a chamber which is adapted to be evacuated and having a cover movable between open and closed positions, the rotor being coupled to a drive spindle which is driven by means located externally of the chamber, the chamber being adapted to be evacuated by a vacuum pump, oil lubricated sealing means forming a vacuum seal about the spindle, said sealing means having provision for introducing oil to and removing oil from the same, an oil reservoir having a fluid connection to said oil sealing means to supply oil to the same, a balanced mounting for said reservoir adapted to assume either one of two positions dependingupon the amount of oil in the reservoir, a fluid connection from the oil sealing means to said vacuum pump for removal of oil from the vacuum sealing means, circuit means for controlling operation of the vacuum pump including a control switch, locking means for locking the cover in closed position, venting means for-the vacuum chamber including an air valve, common manually operated 'means for operating said locking means, for operating said air valve and for operating said controlling switch to interrupt operation of said vacuum pump when said locking means is released, and means for pre venting operation of said last named means when the oil in the reservoir is less than a predetermined amount.

8. In centrifuge apparatus of the type including a centrifuge rotor disposed in a chamber which is adapted to be evacuated and having a cover movable between open and closed positions, means including a manually operated member movable between limiting positions for locking the cover in closed position, means including a manually operated member for actuating said first named member, means including an electrical switch adapted to be operated by movement of-said last-named member in a direction to cause locking of the cover, a vacuum pump connected to the chamber and adapted to be started in operation by operation of said switch, and a venting valve for the vacuum chamber adapted to be moved between closed and venting positions and mechanically connected to be operated by movements of said manually operated member.- I

9. In centrifuge apparatus of the type including a centrifuge rotor disposed in a chamber which is adapted to be evacuated and having a cover movable between open and closed positions, the rotor being adapted to be driven by means under the control of a speed controller whereby the driving speed can be adjusted over a. wide range, means including a member movable between limiting positions for locking the cover in closed position, means including a manually operated member for actuating said first named "member, a pair of electrical switches adapted to be operated by movements of said manually operated member, a vacuum pump for the vacuum chamber, circuit connections from one of said switches to said vacuum pump to start the vacuum pump in operation when said manually operated member is turned to lock the cover in closed position, and circuit connections from said second one of said switches to said speed controller to permit higher speeds of rotation when the cover is closed and locked.

10. In centrifuge apparatus of the type including a centrifuge rotor disposed in a chamber which is adapted to be evacuated and having a cover movable between open and closed positions, the rotor of said chamber being driven by means under the control of a speed controller whereby the driving speed can be adjusted over a wide range, means including a member movable between limiting positions locking the cover in closed'position, means including a manually operated member for actuating said first named member, a switch adapted to be actuated upon operation of said manually operated member, a vacuum pump connected to evacuate the chamber and having circuit connections to said switch whereby the vacuum pump is started in operation when said manually operated member is operated to lock the cover, latch means adapted to lock said manually operated member in a position which it occupies when the cover is fully locked, and circuit means responsive to said speed controller for releasing said latch means when the speed of the rotor is less than a predetermined value whereby for operating speeds below said value the apparatus can be operated with the can in either open or closed position.

11. In centrifuge apparatus of the type including a centrifuge rotor disposed in a chamber which is adapted to be evacuated by a vacuum pump, the chamber having a cover movable between open and closed positions, the rotor being driven by means controlled by a speed controller adjustable over a wide speed range to set the speed of operation, means for locking the cover in closed position, valve means for venting the chamber to the atmosphere, circuit means including a. control switch for controlling operation of the vacuum pump, circuit means including another control switch for conditioning the speed controller to prevent higher speeds of rotation of the rotor beyond a predetermined value, common manually operated means for actuating said locking means and for operating the valve means to vent the chamber and for operating said control switches, whereby when said manually operated means is operated to lock the cover, the vent valve is closed, the vacuum pump is started in operation, and the second control valve is operated to permit said higher speeds of operation, latch means for locking said manually operated means in the position which it occupies when the cover is fully locked, and circuit means actuated by said speed controller for causing release of said latch means when the rotor is operating at a speed below said predetermined speed.

12. In centrifuge apparatus of the type including a centrifuge rotor disposed in a chamber which is adapted to be evacuated and having a cover movable between open and closed positions, means for looking the cover in closed position, a manually operable member movable between limiting positions for operating said locking means, a vacuum pump having a pneumatic connection with the chamber, an electric motor for driving the pump, an energizing circuit for driving the motor, a switch in said circuit for controlling operation of the motor, and means responsive to movement of said manually operable member in a, direction to lock said cover for operating said switch to energize said motor.

13. In centrifuge apparatus of the type including a centrifuge rotor disposed in a chamber which is adapted to be evacuated, the chamber having a cover movable between open and closed positions and the rotor being driven by means controlled by a speed controller which is adjustable to set the speed of operation to a selected value, mechanical means for locking the cover in closed position, a valve having a pneumatic connection with the interior of the chamber and serving to vent the chamber to atmosphere, a motor for driving the vacuum pump, an electrical circuit for energizing the motor, a first control switch included in said circuit and serving to control energizing of the motor, circuit means including a second control switch for conditioning the speed controller to prevent speeds of rotation of the rotor beyond a predetermined value, a manually operable member movable between limiting positions, means forming an operating connection between said member and said locking means, a, connection between said member and said valve to position the valve to vent the chamber when the cover is unlocked and to close the valve when the cover is locked, and means operating said first control switch responsive to operation of said manually operable member, operation of said first control switch when said member is turned to effect locking of the cover serving to energize the circuit to said motor to drive the vacuum pump, operation of said second switch responsive to turning said member to effect locking of the cover serving to condition said speed controller to permit speeds of operation in excess of said predetermined speed, latch means for locking said manually operated member in the limiting position which it occupies when the cover is locked, and circuit means activated by said speed controller for causing release of said latch means when the rotor is operating at a speed below said predetermined speed.

EDWARD G. PICKELS.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,209,723 Ayres July 30, 1940 2,261,936 Johnson Nov. 11, 1941 2,447,330 Grebmeier Aug. 17, 1948 FOREIGN PATENTS Number Country Date 577,522 Germany June 1, 1933 585,044 Germany Sept. 28, 1933 

